Love is one of the most confusing and wonderful parts of life. There is perhaps no subject about which so many stories, songs and poems have been written. Speculation about it is always an area of fascination, particularly for women.

But what is love and do we really need it? It’s common to hear people say they’re happy to be alone and can live without it.

If you have an interest in this subject, the experiments of famed American psychologist Harry Harlow from the 1950s onwards are worth hearing about. He arguably did more to expand our understanding of the psychological underpinnings of love than anyone before him.

Before I continue, readers should be aware that the experiments I’m going to talk about involve animals – specifically monkeys. Some of these can be viewed as disturbing and cruel, and if you don’t wish to hear about such things, now’s the time to stop reading and explore elsewhere on the site.

Let me say up-front, that I find some of these experiments uncomfortable to hear about also. But the results are so fascinating that they’re difficult to ignore. There could be an interesting ethical debate on this point about whether the ends justify the means, but that’s a subject for another article.

Dr Harlow conducted his experiments on love using infant macaque monkeys, because of the similarity of behavior they display with human children.

“The macaque infant differs from the human infant in that the monkey is more mature at birth and grows more rapidly,” Harlow said in a paper on the subject, “but the basic responses relating to affection, including nursing, contact, clinging, and even visual and auditory exploration, exhibit no fundamental differences in the two species. Even the development of perception, fear, frustration, and learning capability follows very similar sequences in rhesus monkeys and human children.”

Harlow’s interest was mainly in how love developed between mother and child, and the effects of that relationship on later responses to affection. He first got the idea for his experiments when he noticed that baby monkeys separated from their mothers developed emotional attachments to gauze cloths used to keep their cages clean. When the cloths were removed, the monkeys would often throw temper tantrums until they were returned. Harlow speculated that the cloths might be being used as surrogate mothers.

To test his theory, he created two fake mothers for his baby monkeys – one made of wire and one made of cloth and warmed from within by a light bulb. Both “mothers” were given a face, and a “breast” in the form of a bottle from which the babies could feed. Both fulfilled all the biological needs of their “children”, feeding them and so forth, but only the cloth mother was made with comfort in mind. The monkeys showed very little interest in the wire mothers, but developed strong attachments to the cloth mothers – clinging to them tightly and becoming distressed when they were removed.

Even if two mothers were provided – a wire one with milk and a cloth one without – the monkeys would prefer the latter. The conclusion was that comfort was much more important to the babies than other variables such as feeding.

If Harlow separated baby monkeys from their new cloth mothers, even for long periods, the importance of the relationship was never forgotten. As soon as their surrogate mother was returned, the monkeys would immediately rush to cling desperately to her.

The babies given cloth mothers also grew to be more psychologically stable than those who had only wire mothers. This was demonstrated when they were put into dangerous and strange situations, such as having noisy toy-robots put into the cages with them. Those with cloth mothers to cling to during the ordeal showed a much greater level of bravery, and much less negative emotion, than those who had no surrogate comfort mother present. The level of psychological security given by these immobile mother figures was found to be very high.

Monkeys who had been raised alone, with no such cloth surrogate, showed no emotional response when one was initially introduced to their cages. Although in time, they could also be shown to develop a strong attachment.

In observation, the level of affection displayed in babies raised by a surrogate mother was very similar to that between a real mother and baby. Both types grew to be more psychologically and physically healthy than those who were denied any type of mother, even though all biological needs were taken care of in all the subjects.

At this point, Harlow’s experiments grew darker. He began to design surrogate mothers that he called “Iron Maidens”. These were mothers with all the comfortable features of the cloth mothers, but who also had the ability to turn evil. Without warning, they would prod their babies with metal spikes or blow cold air against them so hard that they were pushed against the side of the cage.

Despite the cruelty of his “Iron Maidens”, Harlow noticed something interesting. No matter how abusive the evil mothers were, the baby monkeys always came back and displayed affection towards them.

Even in the face of abuse, the need for love was overwhelming. It seemed anything was preferable to being without it.

Another interesting result came from these “tough-love” experiments. The worse the mothers abused their “children”, the more needy those children became. This showed the myth that you can toughen people up against love by denying it to them is wrong. We need it, and removing it will just damage us, not make us stronger.

Harlow’s experiments, while sometimes dark, tell us a basic truth about ourselves. We are not just robots engaged in a mindless search for fulfilling our biological requirements. Instead, love is at the very center of our being. In fact, it can be shown to be more important to us than even our more basic physical needs.

Harlow’s means were definitely disturbing, but his results tell us something beautiful about what it means to be alive.